Auricular Ear Stimulation and fMRI study

Modern goddess statue — Ancient Medicine Made Modern

This study is from 2007, interesting since I am developing a TENS ear stim device in the clinic. Though I think acupuncture has more profound effects, I’m hoping this device will make it possible to extend acupuncture’s effects for a longer interval. This study shows the effect on the brain that leads to a feeling of well being. A few patients have bought units to take home because they like the boost it gives them.
This article says to use the left ear. I usually use the right one, so perhaps I should switch and tell the “home users”to do the same and see if it makes any difference.

J Neural Transm. 2007;114(11):1485-93. Epub 2007 Jun 14.

BOLD fMRI deactivation of limbic and temporal brain structures and mood enhancing effect by transcutaneous vagus nerve stimulation.

Kraus T¹, Hösl K, Kiess O, Schanze A, Kornhuber J, Forster C.

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Abstract

Direct vagus nerve stimulation (VNS) has proved to be an effective treatment for seizure disorder and major depression. However, since this invasive technique implies surgery, with its side-effects and relatively high financial costs, a non-invasive method to stimulate vagal afferences would be a great step forward. We studied effects of non-invasive electrical stimulation of the nerves in the left outer auditory canal in healthy subjects (n = 22), aiming to activate vagal afferences transcutaneously (t-VNS). Short-term changes in brain activation and subjective well-being induced by t-VNS were investigated by functional magnetic resonance imaging (fMRI) and psychometric assessment using the Adjective Mood Scale (AMS), a self-rating scale for current subjective feeling. Stimulation of the ear lobe served as a sham control. fMRI showed that robust t-VNS induced BOLD-signal decreases in limbic brain areas, including the amygdala, hippocampus, parahippocampal gyrus and the middle and superior temporal gyrus. Increased activation was seen in the insula, precentral gyrus and the thalamus. Psychometric assessment revealed significant improvement of well-being after t-VNS. Ear lobe stimulation as a sham control intervention did not show similar effects in either fMRI or psychometric assessment. No significant effects on heart rate, blood pressure or peripheral microcirculation could be detected during the stimulation procedure.

CONCLUSIONS:

Our study shows the feasibility and beneficial effects of transcutaneous nerve stimulation in the left auditory canal of healthy subjects. Brain activation patterns clearly share features with changes observed during invasive vagus nerve stimulation.